Question whether you want to uproot your family for a 2 year contract, with no guarantee it will be extended.

I think you also have to ask yourself when you intent to retire as that may infulence your decision.

If you return to Austrslia in 2 years time ask yourself how easy it will be to get a job. Like it or not in Australia I think you would be hard pressed given your age. I do not thinkl it is right but in reality the age thing does factor into people minds when recruiting.

Something to consider.

Good luck